1. Field of the Invention
The present invention relates to a flat display unit and a method for fabricating the same.
Display devices such as plasma display, liquid crystal display, EL (electroluminescence) display and FED (field emission display) are being paid attention as the devices for wall type display apparatus, as is well known.
However, these devices usually have a structure composed of one or a pair of glass substrates adhered to each other and, therefore, are mechanically weak, and an improvement to reinforce the mechanical strength of the devices is needed.
2. Description of the Prior Art
Prior art flat display unit will be explained with reference to FIGS. 9A, 9B, 10A and 10B by taking a plasma display unit as a typical example, in which FIGS. 9A and 9B are a perspective view and a sectional view thereof, respectively, and FIGS. 10A and 10B are a perspective view and a sectional view, respectively, both showing a protector attached to the display unit during the assembling process of the display unit.
As shown in FIGS. 9A and 9B, plasma display unit 51 has an integrated structure of a display panel 53 and a circuit board 54 which are combined through a chassis 52, where display panel 53 is composed of a front substrate 53a and a rear substrate 53b which are adhered to each other with a discharge space therebetween, and circuit board 54 has a plurality of driver circuits mounted thereon for supplying a predetermined voltage to display panel 53.
Further explaining in detail, display panel 53 is adhered to a surface of chassis 52 through the entire area of rear substrate 53b by using a bonding material such as a double-faced adhesive tape, while circuit board 54 is secured to another surface of the chassis by screw stop method, for instance.
As shown in FIG. 9B, chassis 52 is composed of a plate formed from a light metal such as aluminum and larger than the display panel. Chassis 52 is occasionally made having a structure in which a number of strips of metallic boards are assembled to form a lattice; thus, room is provided in the chassis and the heat dissipation characteristic thereof can be improved.
Display panel 53 and circuit board 54 are electrically connected to each other by a flexible cable 55, and a predetermined voltage is applied to the display panel 53 from circuit board 54.
In display panel 53, as shown in FIG. 9A, front substrate 53a and rear substrate 53b are bonded to each other such that respective ones of pairs of opposing edges of substrates 53a and 53b protrude from the respective corresponding edges of the counterpart substrates 53a and 53b, for instance. A group of display electrode terminals are exposed on the surface of the substrate in the protruding part, and the wiring at an end of flexible cable 55 is connected to the exposed terminal group, by applying a thermo-compression bonding of anisotropic conductive adhesive material.
The wiring at another end of flexible cable 55 is connected to circuit board 54 secured to another surface of chassis 52, via a not-shown connector.
Although only one respective circuit board 54 and flexible cable 55 is shown in FIGS. 9(a) and 9(b), a plurality of circuit boards are mounted on chassis 52 and a plurality of flexible cables are connected to these circuit boards, practically.
Display panel 53 is composed of a front substrate 53a and a rear substrate 53b adhered to each other, each formed of a glass plate, and is weak in the mechanical strength thereof, and therefore, the panel is equipped with a protector, during the processes for the integration with circuit board 54 after the assemblage of the panel, during the transfer among subsequent processes, and during the various tests and inspections, and thus is protected from the damage thereof.
FIGS. 10A and 10B are a perspective view and a sectional view, both showing a plasma display unit equipped with a protector.
Referring to FIGS. 10A and 10B, protector 56 is box-shaped and has a bottom surface provided with an opening, and a chassis 52 mounted with display panel 53 is set in the protector such that the front substrate of display panel 53 exposes from the opening in the bottom surface of the protector, and then, a plurality of securing pins 57 are screwed into at least a pair of opposite sides of the protector so as to pass therethrough and press to hold chassis 52 from the corresponding sides of chassis 52. Thus, display panel 53 is in a state where it is protected by protector 56.
After that, a circuit board 54 is mounted on chassis 52 through the opposite upper surface of protector 56, and secured thereto by screw-stop means, and then, one end of flexible cable 55 having another end connected to display panel 53 by a thermo-compression bonding, in advance, is connected to circuit board 54, and thus, the state of the display panel 53 equipped with a protector as shown in FIGS. 10A and 10B is completed.
In the state equipped with a protector, display panel 53 mounted on chassis 52 is transferred to the instruments for tests and inspections and is subjected to a test to be turned on, for instance. It is of course intended that display panel 53 is protected by the protector during the processes including such transfer and tests.